GLAUCOMA

GLAUCOMA

This condition is the second most common cause of permanent vision loss.

 
Glaucoma is a disease in which there is optic nerve damage which cannot be reversed. The optic nerve is responsible for the function of carrying visual impulses from the nerve to the brain.  The majority of the cases experience visual loss due to an increased pressure in the eye, called intraocular pressure or IOP.

There are 4 types of  Glaucoma:

• Open-angle (chronic) glaucoma
• Angle-closure (acute) glaucoma
• Congenital glaucoma
• Secondary glaucoma

The clear fluid which fills the anterior part of the eye is called aqueous humor.  This liquid is produced by the iris and exits the eye through an area called the anterior chamber angle or just the angle.  Anything that slows or blocks the flow of this fluid out of the eye will cause pressure to build up in the eye. This pressure is called intraocular pressure (IOP).  In most cases of glaucoma, this pressure is high and causes damage to the optic nerve.

Open-angle (chronic) glaucoma is the most common type of glaucoma.

 RISK

Certain factors can make it more likely that a person may develop Glaucoma.  Those risks include:

 

• Having family history of glaucoma damage
• having optic nerve or visual field findings on the border between glaucoma and normal
•  African-American ethnic background
• Being myopic (near-sighted)
• Having a thin cornea
• Being at higher risk of developing high IOP due to a condition in which pigment is dispersed  

If glaucoma is caught when the signs are very early and treatment begun at that time, the risk of developing serious visual loss is quite small.

OPEN ANGLE GLAUCOMA:      

This is the most common type and constitutes about 90per cent of all cases.  The patient experiences no real symptoms but the IOP

becomes elevated until visual loss occurs.  This happens in both eyes or the condition is bilateral.  This is caused by the degeneration or rigidity of trabecular meshwork, Schlemm’s canal and venous channels.  Although the production of aqueous is constant, the outflow decreases so IOP goes up. The treatment for this condition is usually prescribed drops or surgery. 

The drops help to reduce production of aqueous and increase drainage through outflow channels.  Drops commonly prescribed are called Diamox which is a miotic drug.

ANGLE CLOSURE GLAUCOMA:

 This condition results in a sudden increase in IOP due to blockage of anterior chamber angle.  Unlike Open Angle Glaucoma, this type has very pronounced and deliberate symptoms.  All outflow of aqueous ceases or stops.  This immediately increase the IOP which causes pain and visual loss.  This usually develops in patients with a narrow (shallow) anterior angle.  There is a sudden onset of symptoms which include a swollen, edematous cornea, reddening of the eye, nausea and vomiting.  The treatment includes dehydrating the eye and using a miotic drug which pulls the iris away from canal of Schlemm.  Surgery is also an option.